President-elect Donald Trump congratulated Sen. John Thune on winning election to the role of Senate majority leader, declaring that the lawmaker "will do an outstanding job."

Who senators choose, and whether Trump ultimately endorses a candidate in the final hours, could set the tone for Trump’s attempts to assert control over the legislative branch.

Republican Sen. John Thune of South Dakota was elected new Senate majority leader, replacing Sen. Mitch McConnell of Kentucky, who is stepping aside.